Lubricant containing pseudopimaric acid and the preparation thereof



Patented May 26, 1936 UNITED STATES LUBRICANT CONTAINING PSEUDOPMARIC ACID AND THE PREPARATION THEREOF Edward A. Brennan and Washington Hull, Savannah, Ga.

No Drawing. Application February 28, 1934, Serial No. 713,302

25 Claims.

The present invention relates to lubricants, and more particularly to a grease, and to high pressure liquid lubricants made from pseudopimaric acid.

It is well known that grease, such as axle grease and similar greases have been manufactured from a petroleum lubricating oil set through the medium of a lime soap made, for instance, by saponification of rosin oil with milk of lime. The rosin oil generally used for this purpose is obtained by the distillation of rosin and is known in the trade as kidney oil. Such oil usually possessed a grease-setting acid value of between 40 and 50%. In their U. S. Letters Patent No. 1,381,504, Rogers and McNeil state that a greasesetting acid value of about 70% can be secured by subjecting rosin to a temperature of about 500 F. for about 24 hours. So far as we are aware, no one has hitherto succeeded commercially in obtaining from rosin a wholly satisfactory product having a higher grease-setting acid value than about 70%.

It is also well known that petroleum lubricants thin out rapidly with increase in temperature and that a given lubricant is not equally adaptable for the cold starting conditions of a machine, such as an automobile engine, and the warm operating temperatures. Some attempts have been made to improve temperature-viscosity characteristics of "lubricants. Among the prior attempts, the following may be mentioned: .(1)

.To motor oils a small amount of kerosene was added to produce so-called iso-viscous lubricant. n (2) Liquid lubricants have been prepared by synthesizing hydrocarbons which have somewhat improved viscosity indices, that is, variation of viscosity with temperature. (3) Solid fillers such as zinc oxide have been used to produce body over a wide range of temperature. (4) Certain soaps like lead oleate have been added to petroleum lubricants to produce not only a better viscosity index, but also to contribute tothe mechanical and chemical structure intended to function under high pressure and high speed of operation. None of the prior results, as far as we are aware, is entirely satisfactory in that the objective has not been achieved or the final lubricant has lacked stability.

We have discovered that improved lubricants can be produced by utilizing soaps made from pseudopimaric acid which we have found posacid give body to lubricants, and that such soaps when incorporated with an oily lubricant produce a product which is suitable as a high pressure liquid lubricant.

It is an object of the present invention to provide a lubricant which is made from an oil and a salt or soap of pseudopimaric acid, which has 5 a grease-setting acid value of approximately 90 percent to practically 100 percent. I

It is another object of the present invention to provide a grease, particularly an axle grease and similar cold-set greases as well as cup greases, 10 pressure greases, mill greases, hot and cold neck greases, and the like, which possesses greater stability and less subject to oxidation and other detrimental changes than those used hitherto.

Other objects and advantages of the invention 15 will become apparent from the following description.

Our improved grease may be produced by any of the conventional methods for the manufacture of rosin oil greases; For a better under- 23) standing of the invention, however, the following description will be given.

A saponifier may be prepared by preferably intimately mixing hydrated lime with a portion of incorporated in about.87 parts by weight of the.

mineral. oilpreferably by heating the mixture to abo'utfQOffiC. To the heated mixture about '3 to about -1'0 parts by weight of a saponifier, such as described hereinabove are added. After agitating the mixture vigorously, it sets in a few minutes 40 as a soft grease. The hardness of the resulting grease depends upon (among other factors) the amount and purity of the pseudopimaric acid used and-upon the proportion of saponifler (i. e.

of lime) to the pseudopimaric acid present.

The great advantage of pseudopimaric acid,

over rosin oil is evident from a comparison of according to the present invention from about 3 I 94.5 parts of mineral oils. In other words, about 100 parts by weight of finished grease according to prior common practice contains only about 67.5 parts by weight of the mineral lubricating oil, whereas about 94.5 parts by weight of oil are contained in a grease made in accordance with our improved process. The grease prepared by our process, when fully cooled and set, is ready for use in any of the usual ways.

The properties and uses of the new greases vary with the amount and character of the ingredients and the manner of compounding.

Thus, the proportion of petroleum or other oil in the mixture may vary up to about 95% by weight and that of pseudopimaric acid may be as low as about 3%. If less than about 3% by weight of pseudopimaric acid is used, say 1.5% to 2%, with a medium to light lubricant, the structure is not rigid but is fluid. It has a body which is retained even at elevated temperatures. Thus high pressure fluid lubricants may be made having a desirable viscosity index.

In the manufacture of our greases, we may use, in place of pure pseudopimaric acid, acrude or only partially refined acid. Similarly, in place of mineral oil, other oils may be used; and, in place of hydrated lime, other salt-forming'bases. Generally, it is preferred to use sodium, potassium or calcium, but in certain instances other alkali or alkaline earth metals may be used and, in other instances, magnesium, aluminum, cadmium, zinc, manganese, cobalt, nickel, iron and lead may be employed. For instance, pseudopimaric acid soaps may be used in combination with fats or soaps of fatty acids such as tallow, stearic acid, lard, oil, cotton seed oil, and the like, to produce mill greases.

-Soaps other than lime soap may also be used.

For example, sodium, potassium, aluminum, zinc, lead soaps and the like may be used. Not only may grease be prepared as described hereinabove, but it may be further processed to dehydrate it and to free it of excess lime by the usual process of drying and separation to produce a clear golden grease of exceptional quality.

The pseudopimaric acid has the following properties: The crude pseudopimaric acid melts at about 69-7l C. while the partially purified pseudopimaric acid melts at about 169-l81 C. and has an optical angle of rotation, (a) D, of about plus to plus 50. More fully refined, it melts at 195.5 to 198 C. (corn), has an optical angle of rotation, (11! D. of about plug 0.33, and an elementary composition which corresponds approximately to the formula CaoHaoCa. When dehydrogenated by heating with sulfur, it gives retene. The ammonium salt as described hereinabove is crystalline. The pseudopimaric acid referred to herein and the method of producing such acid are fully described and claimed in the co-pending application of Brennan et al.,Serial No. 675,976.

It is to be observed that the present invention provides an improved grease-setting medium, pseudopimaric acid, which possesses great value and utility in the manufacture of a great variety of greases including axle grease, coldset grease, cup grease, hot and cold neck grease, lubricating grease, and the like. I

It is also to be noted that the present invention provides a grease which is more stable and less subject to oxidation than greases known heretofore.

Furthermore, the present invention provides an improved method of manufacturing greases, in which a cold-set lime grease, for example, can

be prepared by using as low as about 3% of the grease-setting pseudopimaric acid. 5

The pseudopimaric acid may be employed as a grease-setting medium either in crude condition or in various degrees of purity. Generally speaking, the purer the acid the smaller the amount necessary to set a grease. 10

Although the present invention has been described with respect to certain preferred embodiments of the invention, it is to be understood that modifications and variations may beresorted to which are within the purview of the 15 appended claims.

' a salt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula CzoHsoOz, and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, lain, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, ialn, of about plus 0.33".

3. A lubricant comprising a lubricating oil and a salt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula CroHaoOz. and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, min, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, [(111), of about plus 0.33.

4. A lubricant comprising a lubricating oil and a calcium salt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula CroI-IaoOz, and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, ml, of about plus 25 to plus 50 and having in its refined state a melting point 50 of about 195 C. to about 198 C. and an optical angle of rotation, [1110, of about plus 033.

5. A lubricant comprising up to about 95% by weight of mineral oil and not less than about 5% by weight of a pseudopimaric acid salt, said acid having an .elementary composition corresponding approximately to the formula C20H30o2, and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, ialn, of about plus 25 to plus 50 and having in its refined state a melting point 'of about 195 C. to about 198 C. and an optical point of about 169 c. to about 181 0. and an optical angle of rotation. ialn, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, [1111. of about plus 033.

7. A lubricant comprising up to about by weight of lubricating oil and not less than about 5% by weight of a pseudopimaric acid salt, said acid having an elementary composition corresponding approximately to the formula CzoHzoOa, and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, ialn, of about plus 25 to plus 50 and having in its refined state a melting point of about C. to about 198 C. and an optical angle of rotation, [0.10, of about plus 033.

8. A lubricant comprising up to about 95% by weight of lubricating oil and not less than about 5% by weight of a calcium salt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula CzoHzoOz, and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, ialn, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, ialp, of about plus 0.33.

9. A high pressure liquid lubricant comprising over about 95% by weight of lubricating oil and less than about 5% by weight of a calcium salt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula CzoHaoOz and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, [(111), of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, [0113, of about plus 0.33".

10. A lubricant comprising up to about 95% by weight of mineral oil and not less than about 3% by weight of a pseudopimaric. acid salt, said acid having an elementary composition corresponding approximately to the formula CzoHaoOz and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, ialp, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, [1111), of about plus 033.

11. The method of producing a lubricant which comprises compounding a mineral oil with a salt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula 0201-1300: and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, lain, of about plus 25 to plus 50 and havingin its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, ml, of about plus 033.

12. The method of producing a lubricant which comprises compounding a petroleum oil with a salt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula CzoHaoOz and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, [(1113, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, ialn, of about plus 0.33.

13. The method of producing a lubricant which comprises compounding a lubricating oil with a grease,said acid having in its crude state a meltsalt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula C2oH30Q2 and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of 5 rotation, lain, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, [a]n, of about plus 0.33".

14. The method of producing a lubricant which comprises compounding a lubricating oil, pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula C2oH3oO2 and milk of lime to form a 1 5 ing point of about 169 C. to about 181 C. and an optical angle of rotation, Min, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, Min, of about plus 0.33.

15. The method of producing-a lubricant which comprises compounding a mineral oil, pseudopimaric acid, said acid having an elementa y composition corresponding approximately to the 25 formula CzoHsoOz and a salt-forming base to form a grease, said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, [a112, of about plus 25 to plus 50 and having in its refined 30 state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, min, of about plus 033.

16. The method of producing a lubricant which comprises compounding a petroleum oil, pseu- 3 dopimaric acid, said acid having an elementary composition corresponding approximately to the formula CzoHsoOz, and a salt-forming base to form a grease, said acid having in its crude state a melting point of about 169 C. to about 40 181 C. and an optical angle of rotation, [1111), of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, lain, of about plus 033. 45

17. The method of producing a lubricant which comprises compounding a lubricating oil, pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula C2oH3oQ2 and a salt-forming base to form 50 a grease, said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, [a113, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 c. to about 198" c. 55 and an optical angle of rotation, lain, 'of about plus 0.33.

18. The method of producing a lubricant which comprises compounding a mixture containing up to about 95% by weight of mineral oil and not less 00 than about 5% by weight of a .salt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula CzoHaoOz and said acid having in its crude state a melting point of about 169 C. to 65 about 181 C. and an optical angle of rotation, tale, of about plus 25 to plus 50 and having in its refined state a meltin point of about 195 C. to about 198 C. and an optical angle of rotation, lain, of about plus 0.33". 70

19. The method of producing a lubricant which comprises compounding a mixture containing up to about 95% by weight of petroleum oil and not less than about 5% by weight of a salt of pseudopimaric acid, said acid having an elementary 75 composition corresponding approximately to the formula 02011300: and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, laln, of about plus 25 to plus and having in its refined state a melting point of about 195 C. to

"about 198 C. and an optical angle of rotation,

laln, of about plus 0.33.

20. The method of producing a lubricant which comprises compounding a mixture containing up to about by weight of lubricating oil and not less than about 5% of a salt of pseudopimaric acid; said acid having an elementary composition corresponding approximately to the formula CzoHaoOa and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, [(111), of about plus 25 to plus 50 and having in its refined state a melting point of about C. to about 198 C.

and an optical angle of rotation, laln, of about plus 0.33.

21. The method of producing a lubricant which comprises compounding a mixture containing up to about 95% by weight of lubricating oil and not less than about 5% by weight of a calcium salt of pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula CaoHsoOz and said acid having in its crude state a melting point of about 169 C. to about 181 C; and an optical angle of rotation, [almof about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, [4111), of about plus 033.

22. The method of producinga lubricant which comprises compounding a mixture containing up to about 95% by weight of lubricating, oil and not less than about 3% by weight of a calcium salt 'of pseudopimaric acid, said acid having an elementary composition corresponding approximate- 1y to the formula 020K300: and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, laln, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, [a]n, of about plus 0.33.

23. As an article of manufacture, a grease-setting medium which has been prepared with pseudopimaric acid, said acid having an elementary composition corresponding approximately to the formula CaoHaoO: and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, [4111), of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, [4111), about plus 0.33".

24. As an article of maniacture, a golden grease containing a salt of pseudopimaric acid, said acid having an elementry composition corresponding approximately to the formula CzoHaoOa and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, [M9, or about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, Min, of about plus 0.33.

25. As an article of manufacture, a high pressure liquid lubricant containing a salt of pseudopimaric acid, said acid having anelementary composition corresponding approximately to the formula Cz HsoOz and said acid having in its crude state a melting point of about 169 C. to about 181 C. and an optical angle of rotation, [a113, of about plus 25 to plus 50 and having in its refined state a melting point of about 195 C. to about 198 C. and an optical angle of rotation, [ll-1n, of about plus 0.33". i

EDWARD A. BRENNAN. WASHINGTON HULL. 

